Spina Bifida (Neural Tube Defect)

What causes spina bifida?

The exact cause of spina bifida remains a mystery. No one knows what disrupts complete closure of the neural tube, causing a malformation to develop. Scientists suspect that the cause is multifactoral: genetic, nutritional, and environmental factors play a role. Research studies indicate that insufficient intake of folic acid -- a common B vitamin -- in the mother's diet is a key factor in causing spina bifida and other neural tube defects. Prenatal vitamins that are prescribed for the pregnant mother typically contain folic acid as well as other vitamins.

What are the signs and symptoms of spina bifida?

The symptoms of spina bifida vary from person to person, depending on the type and level of involvement. Closed neural tube defects are often recognized or identified early in life due to an abnormal tuft or clump of hair or a small dimple or birthmark on the skin at the site of the spinal malformation.

Meningocele and myelomeningocele generally involve a fluid-filled sac-visible on the backprotruding from the spinal canal In meningocele, the sac may be covered by a thin layer of skin. In most cases of myelomeningocele, there is no layer of skin covering the sac and an area of abnormally developed spinal cord tissue usually is exposed.

What are the complications of spina bifida?

Complications of spina bifida range from minor physical problems to severe physical and mental disabilities. It is important to note, however, that most people with spina bifida have normal intelligence. Children with myelomeningocele and/ or hydrocephalus (excess accumulation of cerebrospinal fluid in and around the the brain) may have learning disabilities, including difficulty paying attention, problems with language and reading comprehension, and trouble learning math.

Spina bifida's impact is determined by the size and location of the malformation, whether it is covered by skin, and which spinal nerves are involved. All nerves located below the malformation are affected to some degree. Therefore, the higher the malformation occurs on the back, the greater the amount of nerve damage and loss of muscle function and sensation.

In addition to abnormal sensation and paralysis, another neurological complication associated with spina bifida is Chiari II malformation -- a condition common in children with myelomeningocele -- in which the brain stem and the cerebellum (hindbrain) protrude downward into the spinal canal or neck area. This condition can lead to compression of the spinal cord and cause a variety of symptoms, including difficulties with feeding, swallowing, breathing control, choking, and changes in upper extremity function (stiffness, swelling).

Chiari II malformation may also result in a blockage of cerebrospinal fluid, causing hydrocephalus. The buildup of fluid puts damaging pressure on the brain and spinal cord. Hydrocephalus is commonly treated by surgically implanting a shunt-a hollow tube -- in the brain to drain the excess fluid into the abdomen.

Some newborns with myelomeningocele may develop meningitis, an infection in the meninges. Meningitis may cause brain injury and can be life-threatening.

Additional problems such as latex allergies, skin integrity breakdown, gastrointestinal conditions, disorders of sleep regulation, and depression may occur as children with spina bifida get older.

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